Nanoscale-Thick a-Ga₂O₃ Films on GaN for High-Performance Self-Powered Ultraviolet Photodetectors

A super-high-performance self-powered ultraviolet photodetector constructed on a p-GaN/a-Ga 2 O 3 p-n heterojunction was fabricated by growing nanoscale-thick films of n-type a-Ga 2 O 3 on p-type GaN film using magnetron sputtering at room temperature. This device exhibited a self-powered effect and dual-band UV detection capability. The device showed exceptional photodetection performance with a responsivity of 5.65 A/W, I light / I dark ratio of 2.03 × 10 2, and a detectivity of 8.46 × 10 12 cm Hz 1/2 W –1 to 254 nm light irradiation and a responsivity of 43.8 A/W, I light / I dark ratio of 1.53 × 10 3 and a detectivity of 6.56 × 10 13 cmHz 1/2 W –1 under 365 nm UV light irradiation of 50 μW/cm 2 light intensity at 0 V, respectively. This outstanding photodetection performance might be ascribed to the distanced separation between photogenerated charge carriers that occurs due to the built-in electric field across the depletion region of the p-n junction of the GaN/a-Ga 2 O 3 thin film. This study shows the GaN/a-Ga 2 O 3 thin-film-based p-n heterojunction UV photodetector with both self-powered performance and dual-band UV photodetection is very promising for practical applications.